<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>浮动-2</title>

    <style>
        .box{
            width: 100px;
            height: 100px;
            border: 1px solid;
            margin: 10px;
        }

        .left{
            float: left; /*left right*/
        }

        .clear-fix{
            clear: both; /*left right both*/
        }
    </style>
</head>
<body>

<div class="box left">
</div>
<div class="box clear-fix">
    hello world
</div>
</body>
</html>